1. The Field of the Invention
The present invention relates generally to kayak paddles and particularly relates to an improved kayak paddle having an ergonomic grip arrangement to facilitate consistent and comfortable placement and orientation of the user's hands on the paddle.
2. The Relevant Technology
Kayakers exhibit a wide range of skill levels, from the recreational kayaker to the professional competitor. Kayaking enthusiasts pursue their sport in a variety of settings, including creeks, rivers, and the ocean. Each of the settings presents unique challenges to the kayaker. In creeks and rivers, the kayaker often faces swift currents, rapids, boulders, and snags. The sea kayaker may encounter strong tides, riptides, and high winds. These obstacles can present a serious threat to the safety of the kayaker who is ill-prepared to meet them.
In order to overcome these obstacles, it is essential that the kayaker be able to effectively control the kayak with a minimum of effort; this is no less true for the recreational kayaker than it is for the expert. The essential element in kayak control is the kayak paddle. A kayak paddle that the user can easily and efficiently employ will greatly facilitate control of the kayak.
It is generally acknowledged that the orientation of the kayaker's grip on the shaft of the kayak paddle is a critical factor in the useability and efficiency of kayak paddles. Accordingly, past efforts have been directed towards developing a shaft so formed as to provide the kayaker with a useful gripping means.
One common configuration is a round shaft that has been compressed in two places so as to deform the round cross-section, at those points, into generally oval-shaped cross-sections. The purpose of the oval cross sections is to provide regions where the user can more easily grasp the shaft. The oval grip portions are also intended to help visually indicate the points on the shaft where the user's hands should be placed. Finally, the grip portions aim to assure the user that the blades will be in the same position each time the grips are engaged, because the radial location of the grip portions, relative to the blades, is fixed.
Another typical configuration employs a round shaft with shims located on the shaft where the users's hands should be placed. The shims are typically secured in place on the shaft by something akin to a shrink wrap process. As with the oval-shaped sections discussed above, the purpose of the shims is both to facilitate gripping of the shaft, to help visually indicate where the user's hands should be placed, and to provide some assurance that the blades will be consistently positioned.
Finally, a more radical design uses a generally straight shaft which has bent portions near either end to provide gripping regions for the user's hands. The bent shaft has a generally round cross-section which flattens slightly through the gripping regions.
Although prior efforts have resulted in some improvement of the kayaker's grip on the shaft, each suffers from inadequacies. The oval cross-section and shim-type grip designs somewhat improve the kayaker's grip and help indicate where the kayaker's hands should be placed, but do little to prevent the user's hands from sliding longitudinally on the shaft. When the kayaker's hands are free to slide along the shaft, control and use of the paddle become very difficult, particularly in rough conditions such as rapids or whitewater. Even in calm conditions, the kayaker's hands tend to slide down the shaft during the draw stroke, that is, the stroke wherein the kayaker reaches forward with the shaft, dips the blade into the water and pulls, or draws, the shaft down and back. Because they are free to slide, the kayaker's hands tend to slip down the shaft during the draw stroke, rather than to push the shaft down into the water. Naturally, the problem of hand slippage is further aggravated when the shaft is wet, as is commonly the case. Hand slippage and the resulting loss of paddle and kayak control is a source of frustration for beginners and experts alike.
While the bent shaft grip configuration is somewhat more effective at reducing hand slippage than are the oval and shim-type grip configurations commonly used on straight shafts, the problem of hand slippage still has not been adequately addressed.
Another shortcoming of typical kayak paddle grip designs is the problem of shaft rotation. Shaft rotation occurs when kayak paddle blades are subjected to the forces exerted by wind and water; those forces act against the flat part of the blade, thereby imparting to the shaft a tendency to rotate about its longitudinal axis.
Shaft rotation is undesirable because it necessarily causes the blades, fixed to the ends of the shaft, to rotate out of position. Physically strong users can prevent this rotation to some extent by tightly gripping the shaft. However, gripping the shaft tightly to prevent rotation often involves a considerable expenditure of effort on the part of the user who is kayaking in strong currents and/or high winds, conditions commonly encountered by kayakers. In the more likely scenario, the user is unable to resist shaft rotation and is compelled to rotate the shaft to place the blades back into position. The necessity for frequent re-orientation of the shaft is, at least, a source of frustration, and could amount to a dangerous distraction in challenging conditions such as whitewater, rapids, or riptides.
The oval and shim-type grip designs provide little resistance to the shaft's inherent rotational tendency because their cross-sections are substantially similar to a purely circular cross-section, which offers virtually no impediment to shaft rotation. Nor does the bent shaft grip configuration resolve the problem of shaft rotation; the gripping regions of the bent shaft have a cross-section similar to that found in the oval and shim-type grip configurations and thus possess the same inherent lack of resistance to shaft rotation.
The inability of current designs to minimize or prevent shaft rotation, causes the user to lose a large measure of control over the paddle, and thus, over the kayak. Furthermore, by expending time and effort to frequently rotate the shaft back into position, the user also realizes an overall reduction in paddling efficiency. Lack of paddle and kayak control, and reduced paddling efficiency, inevitably result in user frustration and fatigue. Fatigue in particular, can become an important issue, for example, when the user is kayaking in open water and has to contend with strong tides and wind.
Kayak paddle shaft rotation, considered alone, is ample cause for concern to the kayaker. However, the natural and inevitable consequence of shaft rotation, out-of-position blades, is cause for concern as well. Blades which are out of position present a serious problem because they impede the kayaker's ability to respond to rapidly changing conditions. As an example, a kayaker whose craft is rushing towards a rock may have only a second or two to take evasive action; if the paddle blades are out of position, the kayaker may be unable to timely execute the necessary maneuvers. Thus, kayakers must be able to quickly establish and easily maintain consistent blade orientation. Current kayak paddle grip designs do not meet this need.
Hand slippage and shaft rotation are the major unresolved concerns in the field, but there are a number of other problems that existing designs have not adequately addressed, or have not addressed at all. One such problem is that the typical grip design does little to reduce the often substantial stresses that kayaking places on the user's hands, wrists, and arms. If anything, these designs may tend to aggravate the problem. One reason for this is that the typical grips are relatively large in diameter and thus, difficult to grasp and hold. The shim-type grips are particularly bulky to grasp because the shim increases the diameter of the grip region, making the shaft difficult for the user to securely hold. Thus, the user is forced to grip the shaft tightly in order to be able to hold it; the user's tight grip consequently increases the stresses on the user's hands, wrists, and arms.
Not only does their bulk make typical grip configurations troublesome to grip and hold, but those configurations also force the user to grip along an unnatural horizontal line. Because most users' natural grip is along axes slightly oblique to a horizontal line, the horizontal grip induces unnecessary additional stress on the user's wrists, hands, and arms.
The grip spacing, that is, the space between the points at which the user grips the shaft, of typical grip arrangements also tends to force many users' hands and arms into unnatural positions. This is because the grip spacing in typical kayak paddle grip arrangements is generally calculated to provide a one-size-fits-all configuration; such designs are inherently unsuited to meet the ergonomic requirements of many users. Consequently, many users are forced to assume inefficient, unnatural postures on the shaft.
In sum, the bulky grips, generic grip spacing, and unnatural grip positions of the typical kayak paddle grip arrangements all conspire to impose unnecessary stresses on the user's hands, wrists, and arms. The results of this stress range from fatigue to repetitive-use injuries that require medical treatment.
A different type of problem with typical kayak paddle grip arrangements concerns the production processes by which those arrangements are fabricated. The bent shaft configuration is noteworthy in this regard. The air-bag inflated mold process used to produce bent shafts is complex and time-consuming. This type of production arrangement is not well-suited to rapid, high volume, mass production. Consequently, bent shaft kayak paddles are very expensive and thus practically unavailable to many kayakers.
Oval section and shim-type grip arrangements are somewhat simpler to manufacture than bent tubes, but as indicated earlier, involve a number of additional steps beyond the creation of a simple shaft. These additional steps necessarily increase the cost of these types of kayak paddle shafts. Not only are these grip arrangements labor-intensive and expensive to produce, but they also fail to make any provision for ergonomically positioning the user's hands on the shaft.
A final concern in the field of kayak paddles relates to the adhesive bond between the shaft and the blade socket in which it is inserted. It is the case with some designs that the stresses imposed on the paddle blades may break the adhesive bond between the shaft and the socket of the paddle blade in which the shaft is inserted. When the adhesive bond is broken, the shaft and blade are free to rotate with respect to each other, and the paddle is thereby rendered ineffective. The paddle must then be repaired or replaced.